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为探明渭北旱塬免耕秸秆覆盖对春玉米田土壤活性有机碳(LOC)、碳库管理指数(CMI)和作物产量的影响,进而明确该区免耕覆盖的适宜年限,于2001—2010年在陕西合阳县旱农试验站,设置了不同年限处理:1年(S1)、3年(S3)、5年(S5)、8年(S8)和10年(S10)的免耕秸秆覆盖定位试验,以常规耕作(CK)和10年免耕不覆盖(CK0)为对照。结果表明:与CK相比,S1、S3、S5、S8和S10处理0～10cm土层土壤有机碳(TOC)质量分数分别提高7.6%、13.5%、25.4%、48.6%和79.0%;LOC分别提高40.1%、51.5%、102.4%、78.4%和75.3%;CMI分别提高49.4%、61.2%、126.8%、85.4%和75.3%。春玉米产量、全氮、全磷和有效磷分别与LOC和CMI呈极显著相关(P<0.01),而与TOC无显著相关性。本研究表明,LOC和CMI较TOC更能快速准确地反映不同年限免耕覆盖对土壤碳库和玉米产量的影响,可以作为渭北旱塬免耕秸秆覆盖生态效应的评价指标,且该区覆盖年限以5～8年为宜。
In order to explore the effects of no-tillage straw mulching on soil active organic carbon (LOC), CMI and crop yield in the spring maize field and to determine the suitable age of no-tillage mulching in the area, In 2010, at the Hannong Experimental Station in Heyang County of Shaanxi Province, no-tillage was set up for different years of treatment: 1 year (S1), 3 years (S3), 5 years (S5), 8 years (S8) and 10 years Straw cover positioning test, with conventional tillage (CK) and 10 years no-tillage does not cover (CK0) as a control. The results showed that soil organic carbon (TOC) mass fraction increased by 7.6%, 13.5%, 25.4%, 48.6% and 79.0%, respectively, in treatments 0-10 cm soil depth compared with CK; Increased by 40.1%, 51.5%, 102.4%, 78.4% and 75.3%, respectively; CMI increased by 49.4%, 61.2%, 126.8%, 85.4% and 75.3% respectively. The yield of spring maize, total nitrogen, total phosphorus and available phosphorus were significantly correlated with LOC and CMI (P <0.01), respectively, but not with TOC. This study shows that LOC and CMI can reflect the effect of no-till tillage on soil carbon stocks and maize yields more rapidly and accurately than TOC, which can be used as an evaluation index of ecological effect of no-tillage straw mulching in Weibei dry land, Years to 5 to 8 years is appropriate.